Mastering Basic Linux Commands with a Twist

Linux commands form the foundation of efficient system administration and automation. In this blog, we explore essential Linux commands with a unique twist, helping you enhance your command-line skills while tackling real-world scenarios.

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1. Viewing File Content with Line Numbers

To read a file with numbered lines, use:

cat -n filename.txt

Example:

cat -n fruits.txt

This will display the contents of fruits.txt with each line numbered.

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2. Changing File Permissions

Restrict file access to the owner by making it readable, writable, and executable only by them:

chmod 700 filename.txt

Example:

chmod 700 fruits.txt

Now, only the owner can read, write, and execute fruits.txt.

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3. Checking Command History

To see the last 10 commands you executed, run:

history | tail -10

This helps in quickly reviewing recently used commands.

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4. Removing a Directory and Its Contents

To permanently delete a directory along with its contents:

rm -r directory_name

Example:

rm -r my_folder

⚠ Caution: This command irreversibly deletes the directory and its files.

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5. Creating and Displaying a fruits.txt File

To create a file with a list of fruits:

echo -e "Apple\nMango\nBanana\nCherry\nKiwi\nOrange\nGuava" > fruits.txt
cat fruits.txt

This adds multiple fruit names, each on a new line, and then displays the content.

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6. Adding and Appending Content in devops.txt

echo -e "Apple\nMango\nBanana\nCherry\nKiwi\nOrange\nGuava" > devops.txt
echo "Pineapple" >> devops.txt
cat devops.txt

This creates devops.txt with a list of fruits and later appends "Pineapple" to it.

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7. Reversing the First Three Fruits

head -3 fruits.txt | tac

This command takes the first three lines and prints them in reverse order.

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8. Sorting the Bottom Three Fruits

tail -3 fruits.txt | sort

This extracts the last three lines and sorts them alphabetically.

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9. Creating and Displaying a Colors.txt File

echo -e "Red\nPink\nWhite\nBlack\nBlue\nOrange\nPurple\nGrey" > Colors.txt
cat Colors.txt

This creates and displays a file listing different colors.

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10. Prepending "Yellow" to Colors.txt

echo "Yellow" | cat - Colors.txt > temp && mv temp Colors.txt
cat Colors.txt

This adds "Yellow" as the first entry in Colors.txt.

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11. Finding Common Lines Between fruits.txt and Colors.txt

comm -12 <(sort fruits.txt) <(sort Colors.txt)

This command displays lines that appear in both files.

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12. Counting Lines, Words, and Characters

wc fruits.txt Colors.txt

Example output:

  7  7  42 fruits.txt
  8  8  50 Colors.txt
 15 15  92 total

This provides the total number of lines, words, and characters for both files.